drm/radeon/kms: fix DDIA enable on some rs690 systems

DVOOutputControl checks the value of of bios scratch reg 3
on some tables and assumes the encoder is already enabled
if the DFP2_ACTIVE bit is set.  Clear that bit so the table
sets the DDIA enable bit properly.

Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Cc: stable@kernel.org
Signed-off-by: Dave Airlie <airlied@redhat.com>

1 files changed, 8 insertions, 1 deletions

diff --git a/drivers/gpu/drm/radeon/radeon_encoders.c b/drivers/gpu/drm/radeon/radeon_encoders.c
index 319d85d7e759..13690f3eb4a4 100644
--- a/drivers/gpu/drm/radeon/radeon_encoders.c
+++ b/drivers/gpu/drm/radeon/radeon_encoders.c
@@ -1507,7 +1507,14 @@ radeon_atom_encoder_dpms(struct drm_encoder *encoder, int mode)
                 switch (mode) {
                 case DRM_MODE_DPMS_ON:
                         args.ucAction = ATOM_ENABLE;
-                        atom_execute_table(rdev->mode_info.atom_context, index, (uint32_t *)&args);
+                        /* workaround for DVOOutputControl on some RS690 systems */
+                        if (radeon_encoder->encoder_id == ENCODER_OBJECT_ID_INTERNAL_DDI) {
+                                u32 reg = RREG32(RADEON_BIOS_3_SCRATCH);
+                                WREG32(RADEON_BIOS_3_SCRATCH, reg & ~ATOM_S3_DFP2I_ACTIVE);
+                                atom_execute_table(rdev->mode_info.atom_context, index, (uint32_t *)&args);
+                                WREG32(RADEON_BIOS_3_SCRATCH, reg);
+                        } else
+                                atom_execute_table(rdev->mode_info.atom_context, index, (uint32_t *)&args);
                         if (radeon_encoder->devices & (ATOM_DEVICE_LCD_SUPPORT)) {
                                 args.ucAction = ATOM_LCD_BLON;
                                 atom_execute_table(rdev->mode_info.atom_context, index, (uint32_t *)&args);